1. Field of the Invention
This invention relates to a unique form of tamperproof latch and, more specifically, has advantageous use in respect of window constructions.
2. Description of the Prior Art
Numerous types of locking or latching devices for various uses including use on windows and doors have long been known.
U.S. Pat. No. 767,001 discloses a door holder wherein rotation of an operating lever causes a foot member to overcome spring bias and engage a floor to thereby maintain a door in a desired position.
U.S. Pat. No. 8,286 similarly discloses a door bolt wherein rotation of a lever urges the tongue portion of the bolt to project beyond the bolt housing.
U.S. Pat. No. 4,195,867 discloses several embodiments of a door latch wherein a rotatable member is adapted to engage a bolt member to move the same between locked and unlocked positions. In one embodiment a key must be employed before the latch can be operated.
U.S. Pat. No. 748,202 discloses a springless lock which is adapted to be operated by means of various counterweights and linkages. With respect to the locking bolt, a cam member is rotated to reciprocate the same.
U.S. Pat. No. 592,457 discloses a cam which is rotated by means of a pin in order to secure a window sash.
U.S. Pat. No. 637,755 discloses a window sash lock wherein a cam is said to position bolts which are spring biased. The positioning of the cam is effected by means of an externally projecting arm.
U.S. Pat. No. 1,828,152 discloses a pushbutton latch for cabinets wherein movement of the pushbutton is said to urge a cam into contact with a roller which is thereby urged against the force of a coil spring.
U.S. Pat. No. 3,129,470 discloses a multipiece window sash latch wherein a spring biased bolt may be manually engaged by means of projecting tab.
There remains a need for a highly efficient latch assembly which is economical to manufacture, tamperproof and is adapted to be surface mounted in either right or left hand positions while effectively, when used in a double hung window environment, permitting free sliding movement of the windows while resisting tilting movement.